Process of preparing 2-isobutyl-1, 5-pentanediol



United States Patent the temperature at 50-55 C. The mixture was stirred for an additional 2% hours, after which a solution of 10 2,960,540 g. of potassium acetate in 10 ml. of water was added and the whole vigorously stirred for 10 minutes. The PROCESS OF PREPARING 5 organic phase was separated and distilled at atmospheric PENTANEDIOL pressure, resulting 1n the removal of 66 g. of isobutyr- Kent C. Brannock, Kingsport, Tenn., assignor to Eastaldehyde. Distillation of the residue in vacuo gave 66 man Kodak Company, Rochester, N.Y-, a c rp rati n g. of isobutyraldehyde trimer, B.P. 88 C. at 12 mm., of New Jersey M.P. 61 0., and 271 g. (a 59.4% yield) .of 2,4-diisopropyl hexahydropyrano-[2.3-d]-m-dioxin, B.P. 128C. No Drawing. Filed Nov. 2, 1959, Ser. No. 850,051 at 12 mm" D 1.4562 and 725 g of residue.

2 Claims. (Cl. 260-635) 200 g. of 2,4-diisopropyl hexahydropyrano-[2.3-dl-mdioxin was mixed with 100. g. of acetic acid, ml. of toluene, and 0.2 g. of p-toluenesulfonic acid. The mix- This invention relates'to a process of making 2-alkyl- 15 ture was heated under refiux for 2 /2 hours and then 1,5-pentanediols, in which the alkyl group in the 2-p0sidistilled under a column, 53 g. of isobutyraldehydetion is a branched-chain group. This application is a water azeotrop being removed at -65 C. When no continuation-m-part of y copendiflg appllcatlon sel'lal more isobutyraldehyde came over, the residue was re- 742,747, filed June {958, now abandoned; fluxed under a Dean-Stark trap for 2 hours. 22 ml. of I have found that aliphatic aldehydes react wlth 20 water layer was removed. The toluene and excess acetic hydropyfan m the of boron to glve acid were removed by distillation in vacuo, heating the 59! i of gg g g g g g 'F residue to C. under 10 mm. pressure. The residue IOXlIlS. ave u er oun t at w en t e starting aldehyde is a branched-chain aldehyde, the 2,4-dialky1- W E ethy} acetate hexahydropyrano-[23-d]-m-dioxin formed can be hydro- 25 was Su jgcte to y rogenatlon 9 four hours at lyzed by refluxing with acetic acid in the presence of a 150 and 1500 y Raney mckel' The cata' catalytic amount of an acid selected from the group lyst was Y q filtratloil and the Ethyl acetate was consisting of mineral acids and strong organic acids havby dlstlnatlon heatmg at ing ionization constants of at least 1x194, to give The residue, crude S-acetoxy-Z-rsobutyl-l-pentanol, was 2-alkenyl-S-acetoxy-valeraldehyde, which can be hydro- 30 Saponlfied and dlstllled to glve 9 5 of e n genated to the corresponding 2-alkyl-1,5-pentanediol at f -i and 87 gy Of 2450- monoacetate. Saponification of the 2-alkyl-1,5-pentanebuty -L -P at diol monoacetate gives 2 alkyl 1,5 pentanediol. My n 1.4579.

CH(CH:):

H CH1 CH2 n oH, BF: 0 o cm cmcoon n .0110 II g J: I

BC Hr (CHa)zCH-- H) H OH;

111 11 d1 533% Dihydropyran fefel i'u-niiaim CH: CH;

2,960,540 Patented Nov. 15, 1960 invention is illustrated, but not limited, by the following examples.

Example 1.A mixture of 317 g. (4.4 moles) of dry isobutyraldehyde and 168 g. (2 moles) of dihydropyran was added dropwise over a period of 1% hours to a stirred solution of 0.5 ml. of boron trifiuoride-etherate in 20 m1. of ether. Slight cooling was used to maintain I HOCHi-CH-CHLCHLCHLO--CHI CHr-C-CH; H

2-isobutyl-1,5-pentanediol monoacetate l N aOH C H:- H- C H:

2-lsobutyl-1,5-pentanediol was g. of potassium acid sulfate. Workup gave 7 8 g. of 2-isobutyl-1,5-pentanediol.

Example 4.-Similarly, using 0.5 g. of 87% phosphoric acid as catalyst,t72;g. of 2-isobutyl-1,5-pentanediol was obtained.

j Example 5..Simil arly, using 0.25 g. of :trifluoroacetic ;acid as catalyst, 83 g. of 2-isobutyl-l,5-pentanedio1 was ;obtained.

Example 6.--Sirnilarly, the use of 0.75 g. of trichloroacetic acid as catalyst gave 88 g. of 2-isobutyl- 1,'5-

pentanediol.

When the starting aldehyde is a straight-chain aldehyde, a 2,4-dialky1hexahydropyrano-[2;3-d1-m-dioxin is formed, but refluxing with acetic acid does not lead to "the formation of a 2-alkly-1,5-pentanediol.

A mixture of 288g. (4 moles) of n-butyraldehyde and 168 g. (2 moles) of dihydropyran was added dropwise over a 30-minute period to a stirred solution of 0.5 ml. ofboron trifluoride-etherate in 20 ml. of ether, moderate cooling being used to maintain the temperature at 50-55 C. The catalyst was neutralized by stirring with a solution of g. of potassium acetate in 20 ml. of water. Distillation of the organic phase gave 269 g. (a 59% yield) of 2,4-dipropyl-hexahydropyrano [2. 3-d1- m-dioxin, 8.1. 115-121 C. at 4-5 mm., n 1.4578. However, repetition of the subsequent steps of Example 1 gave only high-boiling, viscous products from which no pure compounds couldbe separated.

The 2-alkyl-1,5-pentanedio1s are useful in the manufacture of plastic polyesters. Some of their carboxylic acid esters are useful as plasticizers and as synthetic lubricants.

Echim:

1. A process of preparing 2-isobutyl-1,S-pentanediol, which comprises hydrolyzing with acetic acid, in the presence of a catalytic amount of an acid selected from the group consisting of mineral acids and strong organic acids having ionization constants of at least 1x10 2,4-diisopropyl hexahydropyrano [2.3-d]-m-dioxin, having the formula GH(CHI)2 H CH: 0 C \CH: (011:):011-(311 H H:

hydrogenating the-reaction product to give 2-isobutyl-l,5- pentanediol monoacetate, and saponifying the 2-isobutyl- 1,5-pentanediol monoacetate.

2. A process of preparing '2'-isobuty1-'1,S-pentanediol, which comprises'hydrolyzing with acetic acid, in the presence of a catalytic amount of p-toluenesulfonic acid, 2,4-diisopropyl hexahydropyrano 2.3-6}-m-clioxin, having the formula CH(CH:):

1,5-pentanediol monoacetate, and saponifying .the 2-isobuty1-1,5-pentanediol .monoacetate.

No references cited. 

1. A PROCESS OF PREPARING 2-ISOBUTYL-1,5-PENTANEDIOL, WHICH COMPRISES HYDROLYZING WITH ACETIC ACID, IN THE PRESENCE OF A CATALYTIC AMOUNT OF AN ACID SELECTED FROM THE GROUP CONSISTING OF MINERAL ACIDS AND STRONG ORGANIC ACIDS HAVING IONIZATION CONSTANTS OF AT LEAST 1X10-2, 2,4-DIISOPROPYL HEXAHYDROPYRANO (2.3-D)-M-DIOXIN, HAVING THE FOUMULA 